A UV nanoimprint method is one method of producing a resist film having a predetermined pattern shape on a substrate such as a substrate to be processed and has, for example, the following manufacturing process including steps (a) to (d):
(a) a placing step of placing a resist (photocurable composition);
(b) a mold contact step of bringing the photocurable composition and a mold having a fine concavo-convex pattern formed on its surface into contact with each other;
(c) a light irradiation step of irradiating the photocurable composition with light; and
(d) a mold release step of releasing the photocurable composition and the mold from each other after the light irradiation step.
It is to be noted that the pattern shape of the resist film produced through the manufacturing process including the steps (a) to (d) is formed by transferring the concavo-convex pattern of the mold onto the resist film placed on the substrate.
By the way, upon utilization of the UV nanoimprint method, to reduce a force needed for releasing the mold from the resist cured product in the mold release step (step (d)), i.e., a mold release force has been an important issue. This is because of the following reason. When the mold release force is large, problems such as the occurrence of a defect in the pattern and a reduction in positioning accuracy due to the floating of the substrate from a stage arise.
In addition, in the mold contact step (step (b)) to be performed before the mold release step, the photocurable composition is filled into a gap between the mold and the substrate, and the concavo-convex pattern formed on the surface of the mold. In the mold contact step, however, the following problems concerning the filling property of the photocurable composition have been occurring. It requires a long time period to fill the photocurable composition and a defect occurs owing to imperfect filling of the photocurable composition into a predetermined space.
Meanwhile, the photocurable composition to be used in the UV nanoimprint method is, for example, a composition disclosed in Patent Literature 1 formed of at least one kind of polymerizable compound, a polymerization initiator, and a fluorine-based surfactant. In addition, Patent Literature 1 discloses that a compound in which a hydrocarbon chain is bonded to a perfluoroalkyl chain, or a compound having a structure in which an ethoxy chain, a methoxy chain, or a siloxane is bonded to a perfluoroalkyl chain is used as the fluorine-based surfactant.
On the other hand, Patent Literature 2 discloses that a compound having a perfluoropolyether structure is used as the fluorine-based surfactant.